This section is intended to introduce the reader to various aspects of art, which may be related to the present embodiments that are described below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light.
Many home entertainment devices not only include the capability to communicate with other devices in a home network but also include the ability to receive and/or process available media content from a plurality of sources, including a plurality of providers. The sources and providers may include, but are not limited to, satellite service, cable service, and free to home over the air terrestrial service. The services may operate in the same or different frequency ranges and may use the same or different transmission formats or protocols. The devices for receiving the services often include, but are not limited to, set-top boxes, gateways, televisions, home computers, and the like. Further, many of these devices may include multiple interfaces for different types of externally provided services as well as different types of home networks. These devices may also include additional features internal to the device, such as storage elements, hard drives, compact disk or digital versatile disk drives, and the like.
In order to receive signals from these different services simultaneously in the device, a filtering structure, such as a multiplex filter, is often used to separate the signals. The filtering structures are particularly important if the services operate in separate frequency ranges and/or use separate transmission formats or protocols. For example, a multiplex filter allows for the reception of multiple signal transmissions, including terrestrial transmissions complying with Advance Television Systems Committee (ATSC) standard, Digital Video Broadcasting television standard (DVB-T2), or the Integrated Services Digital Broadcasting television standard (ISDBT) as well as for the reception of satellite signals. A diplex filter, a type of multiplex filter, is often comprised of a high pass filter for a first high frequency band (e.g., a satellite signal frequency band) and a low pass or band pass filter for a second lower frequency band (e.g., a terrestrial or cable broadcast frequency band).
However, a system receiving multiple signals from multiple services over a wide range of frequencies creates significant difficulties in creating a suitable diplex or multiplex filter that provides optimal performance for all services. Previous systems often did not require the additional filtering functions in the devices in order to receive certain terrestrial (e.g., ATSC, DVB-T2, or ISDBT) broadcast signals along with satellite signals on a common co-axial cable input. System operation may be further complicated by the inclusion of an interface to a wired home communication network, such as a Multimedia over Cable Alliance (MoCA) network. For example, frequency guard bands between the frequency ranges for the terrestrial and satellite services may be small and require more selectivity from the filter sections. In configurations that operate with both satellite broadcast and home communication signals, the filtering between these signals may not be sufficient enough to prevent interference to the reception of the satellite signals caused by transmission of the home network signal from the device. For instance, a typical broadcast receiving circuit uses a signal level detector and some form of a gain or signal level adjustment circuit to control the signal level for the satellite signal prior to demodulation in the receiving circuit. Insufficient frequency spacing may not allow suitable filtering for attenuating transmitted home network signal. As a result, signal energy from the transmitted home network signal may be present at the signal level detector and may affect the operation of the signal level detector, particularly at lower signal input levels for the satellite signal. The additional signal energy may cause an incorrect gain setting for the satellite signal level and a degraded performance for satellite signal reception. The problem may be further exacerbated by the type of gain control circuit that is used. Therefore, a solution that mitigates or prevents performance degradation for satellite signal reception in a device when the device is transmitting a home network signal is desirable.